Waste will kill ipv6 too

Fri Dec 29 15:56:26 UTC 2017

On Dec 29, 2017, at 02:27, sthaug at nethelp.no wrote:

>>> My wild guess is if we'd just waited a little bit longer to formalize
>>> IPng we'd've more seriously considered variable length addressing with
>>> a byte indicating how many octets in the address even if only 2
>>> lengths were immediately implemented (4 and 16.)
>> 
>> Actually, that got heaved over the side fairly early in the IPng discussion,
>> because nobody  who was building silicon last century wanted to
>> deal with arbitrary-length addresses.  The IPv4 header had source and
>> destination addresses on 4-byte boundaries for good reasons which
>> still held true when we did the IPv6 headers.
> 
> It's rather interesting how parsing of variable length addresses was
> thought to be way too complicated - while parsing of IPv6 extension
> header chains of unknown length was okay.

Well... first, fast routers mostly don’t parse those chains. Second, to the extent they do, it’s the biggest legitimate complaint I’ve seen with the design of IPv6. 

Owen

> 
> Steinar Haug, Nethelp consulting, sthaug at nethelp.no